Guest Lecture: Guido Hesselmann (Tel Aviv)
Abstract: A fundamental issue in the search for cortical mechanisms underlying perceptual awareness concerns neuroanatomical specificity, i.e. to what extent cortical activity giving rise to awareness is invariant across different cortical systems, or localized to more ‘privileged’ regions. A prominent testing ground for this question has been the fundamental specialization of the visual system into a dorsal ‘action/Where’ stream and a ventral ‘recognition/What’ stream. Specifically, it has been suggested that the ventral stream shows a privileged access to conscious perception, while activity in the dorsal stream may not. Here, we examined this issue using the recently introduced method of continuous flash suppression which offers a particularly sensitive measure of such link. Subjects had to detect images of manipulable objects (tools) which are known to strongly activate ventral as well as dorsal stream areas. Our main finding shows identical patterns of activity in both visual streams, i.e. strong fMRI-BOLD activity for visible tools, but an absence of tool-specific activity in the invisible condition. These data provide strong support to the notion that, at least within high order visual cortex, the link between neuronal activity and perceptual awareness is anatomically invariant. All are welcome!
